N.J. Stat. § 17:12B-163
When the unpaid balance owing upon a loan as defined in section 158 of P.L. 1963, c. 144 (C. 17:12B-158) is repaid in full or the maturity of the unpaid loan is accelerated before the date scheduled for the payment of the final installment, the association shall allow a credit on account of the precomputed interest, the amount of which shall not be less than the amount determined by the application of the formula
AN C = in which D
"C" represents the amount of the credit to be given; "A" represents the amount of precomputed interest; "D" is determined by ascribing to each payment period included in the period for which interest was precomputed, reckoning from the day upon which the loan was made, the cardinal number descriptive of the number of payment periods scheduled, by the terms of the loan, to elapse from the beginning of each such payment period, to the date to which interest was precomputed, and the total of all the cardinal numbers so ascribed constitutes the quantity "D" ; and "N" represents the difference between the quantity "D" and the total of all the cardinal numbers ascribed to the payment periods which have elapsed, in whole or in part, from the making of the loan, to the day upon which such repayment is made, or to the day upon which the maturity of the unpaid balance of such loan is accelerated, as the case may be.
The commissioner may prepare and distribute to such associations as shall make a request therefor, a schedule or schedules based upon the formula specified in this section for use in determining the credit to be allowed pursuant to this section, and allowance of interest made as provided in such schedule shall constitute a complete compliance with this section. A copy of such schedule, duly certified by the commissioner, shall be evidenced in all courts and places.
This section shall not apply where the amount of the credit to be allowed is less than $1.00. The unpaid balance of a nonprecomputed loan may be paid in whole or in part at any time.
If an association knowingly violates any provision of sections 159 through 164 of this act (C. 17:12B-159 through C. 17:12B-164), the association shall forfeit the entire interest which the note or other evidence of debt carries with it, or which has been agreed to be paid thereon, and the borrower, or his legal representatives, may recover back, in an action against the association, twice the amount of interest received by the association on such loan, provided such action is commenced within 2 years from the date such violation occurred. The amount of any interest credit allowed pursuant to section 163 of this act, shall not be deemed to be interest received by the association for the purposes of this section.
N.J.S. § 17:12B-163